The leader of a banned rebel group in Pakistan's southwestern province of Baluchistan has been killed by security forces.

A spokesman, Bohrag Baloch, for the Baluchistan Liberation Army told news agencies Wednesday that Balach Marri was killed during an overnight operation.

Pakistani officials have not commented on the incident. Ethnic Baloch rebels have waged a bloody insurgency against Baluch authorities, seeking more political rights and a share of the region's natural resources.

Meanwhile, in North West Frontier Province, the Pakistani army says troops have driven pro-Taliban militants out of parts of the region in a new offensive launched this week.

Army spokesman Major General Wahid Arshad told VOA that troops have largely ejected militants from urban areas in Swat Valley and Shangla district. He said around 40 militants were killed over the past two days.

Arshad says the army warned local residents to leave some villages in order to isolate militant fighters and prevent civilian casualties. He says the military is bringing in supplies and shelter for those displaced by the fighting -- which has prompted thousands of people to flee.

Unrest erupted in the Swat Valley last month when pro-Taliban cleric Maulana Fazlullah declared a holy war against the government, spreading his message through a pirate FM radio station. Militants loyal to Fazlullah have taken control of large parts of the region over the past month.